Warning: SPOILERS for Better Call Saul season 6, episode 8.
Kim Wexler is far from the worst villain in the Breaking Bad universe, but in Better Call Saul season 6, she's willing to undertake measures that not even Walter White was capable of. Walter White is the greatest example of people's capacity for change as he goes from a meek high school teacher to a murderous villain in Breaking Bad. In the prequel series Better Call Saul, Kim Wexler's arc parallels Walter White's, as she flip-flops between both sides of the law. Kim has yet to commit the heinous crimes that Heisenberg became infamous for - but in Better Call Saul season 6, episode 8, "Point and Shoot," she goes further than Walter White ever did in one shocking way.
Kim's faltering morality has been evident across Better Call Saul season 6, as she doggedly pursues a scheme to destroy Howard Hamlin's reputation, eventually leading to Howard's death. Lalo killing Howard in front of Jimmy and Kim lays the consequences of their actions before their eyes, but instead of atoning for their sins, Lalo forces one of them to travel to Gus Fring's house and shoot him. Kim eventually steps up to do the job after Jimmy argues that "she can do it," and while Kim's visit to Gus' house perfectly plays into Lalo's plan, Kim's resolve is glaring.
Kim approaching Gus' house in Better Call Saul acutely mirrors a Breaking Bad moment when Walter White storms up to Gus' house, gun in hand, with the intention to pull the trigger. Walter is stopped before he even knocks on the door, however, as Mike's phone call spooks him. Mike says, "go home, Walter," while the dark street is completely empty, with Walt oblivious to Gus' intricate surveillance network that is revealed to audiences in Better Call Saul season 6. The fact that Walt halts his plan to shoot Gus early when Better Call Saul shows Kim knocking on Gus' front door ready to shoot demonstrates both the desperation of Kim's situation and the destruction of her moral boundaries.
Why Kim Was Prepared To Kill Gus In Better Call Saul
There's good reason for Jimmy trying to convince Lalo that Kim is the only one up to shooting Gus Fring. It seems that nobody who meets Kim Wexler in Better Call Saul underestimates her anymore. Lalo is seemingly impressed by her brazenness when she confronts him in prison, and in Better Call Saul season 6, Mike tells her (rather than Jimmy) that Lalo is alive because he believes that she's made of "sterner stuff." The fact that Kim was ready to shoot Gus displays what a good judge of character Mike is. Of course, unlike Walt in Breaking Bad, Kim doesn't know who Gus is or what he's capable of when she knocks on his door, but there's no reason to suggest that she would not do the same in a similar situation.
Kim's decision to try to kill Gus in Better Call Saul ultimately stems back to her relationship with Jimmy. The only reason that she went rather than him is that Jimmy wanted her to have a chance to escape, yet he didn't account for the fact that Kim would happily reciprocate the sacrifice. At that moment, Kim is prepared to risk her life for Jimmy and risk shattering the beliefs that she has leaned upon throughout Better Call Saul. Even if this moment is a huge proclamation of Jimmy and Kim's love for each other, the fact that Kim tried to kill Gus could equally hamper any possibility of their happy ending. Gus may be impressed by her resolve and try to use her to his advantage, or he could choose the path that he chose with Walter White in Breaking Bad and will seek revenge for her opposing him.